"There are now more than 700,000 internally displaced by the fighting which began on April 15," Paul Dillon, spokesman for the International Organization for Migration [IOM] said. "Last Tuesday, the figure stood at 340,000," he added.
Even before the beginning of the fighting, 3.7 million people were registered as internally displaced in Sudan, added Dillon.
Another 150,000 people have fled the country since the beginning of the conflict, according to numbers released by the U.N. refugee agency on Monday.
The latest truce talks in Saudi Arabia yielded no progress, with a Saudi diplomat saying both sides consider themselves "capable of winning the battle."
"Many IDPs are sheltering with relatives, while others are gathering in schools, mosques and public buildings," said Dillon.
He said IOM was "conscious of the enormous pressures" placed on host communities "already suffering from the effects of more than three weeks of fighting."
